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Fix bug in TCP implementation (simulations).

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The problem was that only ACKed packets were subtracted from in_flight_, but lost packets were never removed, which caused TCP to stop sending eventually.

R=pbos@webrtc.org

Review URL: https://webrtc-codereview.appspot.com/43239004

Cr-Commit-Position: refs/heads/master@{#9041}
This commit is contained in:
Stefan Holmer 2015-04-21 14:48:23 +02:00
parent e62202fedf
commit 5f92051f06
2 changed files with 8 additions and 11 deletions
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14
webrtc/modules/remote_bitrate_estimator/test/packet_sender.cc
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@ -295,10 +295,12 @@ void TcpSender::UpdateCongestionControl(const FeedbackPacket* fb) {
DCHECK(!tcp_fb->acked_packets().empty()); DCHECK(!tcp_fb->acked_packets().empty());
ack_received_ = true; ack_received_ = true;
in_flight_ -= static_cast<int>(tcp_fb->acked_packets().size()); uint16_t expected = tcp_fb->acked_packets().back() - last_acked_seq_num_;
DCHECK_GE(in_flight_, 0); in_flight_ -= expected;
uint16_t missing =
expected - static_cast<uint16_t>(tcp_fb->acked_packets().size());
if (LossEvent(tcp_fb->acked_packets())) { if (missing > 0) {
cwnd_ /= 2.0f; cwnd_ /= 2.0f;
in_slow_start_ = false; in_slow_start_ = false;
} else if (in_slow_start_) { } else if (in_slow_start_) {
@ -311,12 +313,6 @@ void TcpSender::UpdateCongestionControl(const FeedbackPacket* fb) {
LatestSequenceNumber(tcp_fb->acked_packets().back(), last_acked_seq_num_); LatestSequenceNumber(tcp_fb->acked_packets().back(), last_acked_seq_num_);
} }
bool TcpSender::LossEvent(const std::vector<uint16_t>& acked_packets) {
uint16_t expected = acked_packets.back() - last_acked_seq_num_;
uint16_t missing = expected - static_cast<uint16_t>(acked_packets.size());
return missing > 0;
}
Packets TcpSender::GeneratePackets(size_t num_packets) { Packets TcpSender::GeneratePackets(size_t num_packets) {
Packets generated; Packets generated;
for (size_t i = 0; i < num_packets; ++i) { for (size_t i = 0; i < num_packets; ++i) {

5
webrtc/modules/remote_bitrate_estimator/test/packet_sender.h
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@ -108,19 +108,20 @@ class TcpSender : public PacketSender {
: PacketSender(listener, flow_id), : PacketSender(listener, flow_id),
now_ms_(0), now_ms_(0),
in_slow_start_(false), in_slow_start_(false),
cwnd_(1), cwnd_(10),
in_flight_(0), in_flight_(0),
ack_received_(false), ack_received_(false),
last_acked_seq_num_(0), last_acked_seq_num_(0),
next_sequence_number_(0) {} next_sequence_number_(0) {}
virtual ~TcpSender() {}
void RunFor(int64_t time_ms, Packets* in_out) override; void RunFor(int64_t time_ms, Packets* in_out) override;
int GetFeedbackIntervalMs() const override { return 10; } int GetFeedbackIntervalMs() const override { return 10; }
private: private:
void SendPackets(Packets* in_out); void SendPackets(Packets* in_out);
void UpdateCongestionControl(const FeedbackPacket* fb); void UpdateCongestionControl(const FeedbackPacket* fb);
bool LossEvent(const std::vector<uint16_t>& acked_packets);
Packets GeneratePackets(size_t num_packets); Packets GeneratePackets(size_t num_packets);
int64_t now_ms_; int64_t now_ms_;